Laser cladding of transparent fused silica glass using sub-µm powder

Abstract

Fused silica glass is a commonly used high-performance material. However, due to the high temperature necessary for its production, manufacturing can also be challenging and costly. An attractive approach is additive manufacturing through laser cladding. Laser cladding of transparent fused silica was achieved using a CO2-laser to locally melt the substrate while injecting a stream of fumed silica glass powder into the melt-pool. By the described technique, it is possible to manufacture fully sintered silica glass with deposition rate up to 29 mm3/min. In this work we have studied deposition dynamics and influence of different process parameters on the final deposition quality.

Advances in laser‐based manufacturing techniques for specialty optical fiber

“…The larger separation mitigates the thermal expansion-related deformations and increases the lifespan of the nozzle. The performance of such a coaxial powder nozzle was discussed in detail in Maniewski et al 98 The typical, continuous printing rate demonstrated in our work was as high as 1.3 mm 3 /s when using a discrete coaxial nozzle. 92 Importantly, these rates were achieved using lab-scale setup, and they can be readily improved, for example, by employing more powerful laser enabling operating with larger spot sizes and higher scanning speeds.…”

“…The transparent, pure fused silica coatings and highly densified three-dimensional structures obtained via LC were demonstrated in our earlier work. 98 The hot-zone dynamics that enabled deposition of highly densified silica-based glass are discussed below.…”

“…In the case of the typically used powders, the small angular divergence of the beam caused by angular scattering can lead to the marginal deformation of the melt pool. 98,99 Absorption is, hence, the main factor that majorly influences the printing process. The absorption in LC is a function of absorption cross-section (C a ) and the absorption coefficient for each powder (𝛽 𝑝 ) and substrate target material (𝛽 𝑡 ).…”

“…The partly sintered regions are the effect of lower temperature, insufficient for complete melting, at the perimeter of the laser-induced hot zone. The partly sintered surface can be removed with mechanical polishing as shown in Maniewski et al 98 or by CO 2 laser post-processing, as demonstrated in Maniewski et al 92 By mixing different powders, one can achieve a customizable composition of the printed glass. For example, the obtained Al-doped silica transparent coating on a pure quartz substrate is depicted in Figure 8C, and an ongoing printing of a Ti-doped glass rod is shown in Figure 8D.…”

Supplementary document for Specialty optical fibre fabrication: Preform manufacturing based on asymmetrical CO Laser heating - 5496007.pdf

“…The molten silicon is easily visible in the neck down region to recrystallise the silicon core [7] and is comparable to estab-396 lished draw tower results [16]. the bulk of material is prepared in-house by DPD using sub-427 micron powders [18]. By careful mixing of dry powders, the 428 mechanical as well as optical properties of the sintered glass were engineered and tailored to application [19] using the titania to increase the refractive index of the glass [20].…”